Static behaviour of partially filled steel box-concrete subject to eccentric loading

In this paper, a novel steel-concrete composite structure namely partially filled steel box-concrete (PFSBC) is proposed for structures which are mainly subject to eccentrically loaded compressive force. The cross-section of this kind of structure is a hollow steel box, which is divided into two parts, with one of them filled with concrete. The static behaviour of PFSBC structures was studied by nonlinear finite element method (FEM) and laboratory tests. The nonlinear FEM analysis is focused on the parametric study of its bearing capacity under the action of eccentric load. It can be found from the study that concrete filling ratio (CFR) which is defined as the ratio of filled concrete area to the whole area of the steel box, and the slenderness of the member, besides the confinement coefficient, are the most important parameters that influence the bearing capacity of PFSBC. To calibrate the FEM results, two PFSBC specimens with different slenderness ratios were tested in the laboratory under the action of eccentric load, and the load-displacement curves were measured. The test results coincided highly with the FEM calculated bearing capacity and other mechanical responses, which indicates the correctness and accuracy of FEM calculation.